I've been goofing around with Dave's awesome opaline recipe and an erbium recipe I cooked up. The phosphate opal at 2.6% doesn't do much out of the pot for me in my process which is thin cups and some glassybaby tests. It does, however, make an excellent, beautiful, consistent, striking fire opal in bar form, which I've shown here. I plan on doubling the phosphorus on the next melt and see how it goes for me.

I also melted a 10% transparent erbium. I made an educated guess on how low the erbium would take the expansion and my initial adjustment, before melting, turned out compatible. I'm going to try and lower it 1 point to get it spot on but I was pretty thrilled with that. This stuff is expensive. One less melt to pay for. Erbium also does a color shift from "it's a girl" pink in daylight or incandescent light to a pretty electric fuschia under florescent lighting.

So what I have here is Dave's opal turned into bar and then overlayed and then the same thing but with a hot dip of the erbium pink. I just love the juicy transparent layer on the bottom of this piece.

I'm also loving that this forum is on to page two already. Thanks Pete for breaking this one out. It's pretty convenient to be able to see it all in one place.

I asked if he wanted a royalty if it was mixed by a batch company (which he didn't). Wonder if he'll change his mind with a brand name like that just waiting to be had.

I've had no luck getting this or Pete's base mixed by Spruce Pine or East Bay. Might try Jim again now that the holidays are past. I've priced everything through Seattle Pottery and will get my own small stock of batch ingredients soon. Hope I can catch up to you and share some experiences. Controller went out on my furnace so I'm cold for a couple weeks.

Hmmm...2 pages of threads with hundreds of posts starts to sound like a book, doesn't it?

I got almost the identical color in a strontium phosphate based solely on Dave's using selenium which is a lot cheaper. Getting the calcium out of that glass certainly is a key. Keeping the potassium high works as well in the stuff of Dave's as it does in any traditional high potash/ selenium glass body.

There's some very big changes ( as in tectonic) coming very soon in the retail color industry.
I may consider mixing my clear in small quantities and selling it. that's different than the changes I refer to.

I got almost the identical color in a strontium phosphate based solely on Dave's using selenium which is a lot cheaper. Getting the calcium out of that glass certainly is a key. Keeping the potassium high works as well in the stuff of Dave's as it does in any traditional high potash/ selenium glass body.

There's some very big changes ( as in tectonic) coming very soon in the retail color industry.
I may consider mixing my clear in small quantities and selling it. that's different than the changes I refer to.

What changes are you talking About? I have a hunch as to what it is... someone is going to retire?

I really can't, not because I'm hiding stuff ( I am ) but because I don't know critical details that I'm dying to know. It is still possible for it to not happen to the extent it currently is resolving. I think it will go public in the next few weeks. I view it as huge.

I really can't, not because I'm hiding stuff ( I am ) but because I don't know critical details that I'm dying to know. It is still possible for it to not happen to the extent it currently is resolving. I think it will go public in the next few weeks. I view it as huge.

*********
I didn't mean to expose your good fortune. I think buying Spruce Pine is a good move. Get it with Erbium. It can serve as a sandbag operation in a pinch when Nuclear war comes to the Smoky Mts. You already have the gun.

The percentage in the phosphate Jordan mentions requires multiple strikes (hot-cold-hot-cold) to get dense opaqueness. I first figured it out making furnace beads and that process had a number of strikes as a default. It can be made quite opaque with three or more strikes.

Coming out of the pot clear has other advantages. You can make multi layer transparent/opaque veils by repeat gathers with no reheats (not striking it any further).
I never got to it but I wanted to see what the minimum percentage of phosphate would be to just barely strike. I thought that would open up other avenues. Something like the old Fenton stuff that only struck when it touched the mold.

I have some distant memory that there is a ceiling on how much phosphate you can add. If you dig back in classics to the original post you'll find the link to the original Corning patent that tipped me off on this. I think it mentions a max on phosphate.

I'm laughing at the Brossphate name tag. Could this be my 15 minutes of fame?

No royalties required. I'm just an open source kind of guy. I never would have figured that out without all the other info that everyone posted here over the years prior to that.

Robert Held NECCA confernence 1968 ( pre GAS) . At that presentation Robert Asserted you could Add Up to 5% Phosphate using bone ash 21 ( don't even try) to the base clear BATCH glass without experiencing issues on mismatch.
Attribution:

That' s Robert Held, so you're clear. ( Alive and involved)

I tried it and it worked. The Strontium is indeed a big step ahead, Thanks Dave, Thanks Milos (R.I.P.) . It works too. Fire opals by their vary nature always have the blue / red transmission characteristics.

I'm thinking the strontium has application in transparent glasses too. Volf mentions that it was being used to replace up to half the lead content for TV tube glasses. If I'm remembering correctly, without digging out Volf and comparing numbers, it gives it a greater modulus of elasticity like lead. Not to mention it's probably makes for a more clean "crystal" appearance for transparents.

Mark told me during the color classes that he had only used strontium in his glasses for the last 20 years with the exception of calcium monophosphate which is quite hard to find these days. He, like many , consider calcium to be a really trashy material. My glasses don't have much calcium if any these days. I do use Barium and zinc much more. If I have calcium, it's always in a 1/3 ratio with barium. I tend to use Sodium tri phosphate as opposed to tri sodium phosphate. I'm not much of a fan of sodium either.

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